A wig comprises in general a sheet-like or film-like wig base formed with artificial skin made of thin synthetic resin and hair planted on said wig base. In cases where hair is thus planted on a wig base formed film-like with artificial skin or others, hair flow or hair amount can be freely designed depending upon the user's preferred hair style, using known hair planting arts such as single, half-knot, and split-knot plantings.
For example, if desired to finish in back style, hair is planted from the forehead to the top portion so to extend backward, and to make the hair appear to flow backwards at an angle on side head portions.
Also, in case to form a hair-dividing portion or a hair whorl in a wig base of artificial skin, hair flow or hair density can be freely designed so to extend in the pre-determined direction.
Thus, for a wig base formed sheet-like, film-like, or plane-like with densely woven textile, hair style can be freely expressed depending upon the user's preference by properly mixing known hair-planting arts.
Here, when the hair is in an early stage of thinning, or it is desired to increase hair amount only at a portion of a head, it is annoying to use a wig base formed film-like with artificial skin which has high airtightness, and hence a hair-increasing device mainly comprising light nets excellent in air permeability is used, instead of an artificial skin base as a more convenient hair piece.
As such a hair-increasing device, a net base composed with filaments arranged lattice-like in matrix, or a hair-secured frame formed in the shape of a rib cage by assembling longitudinal linear ribs having rigidity and elasticity is often used.
For example, as is schematically shown in a diagonal view of FIG. 13, the hair-increasing device 30 comprising a rib cage-shaped hair-secured frame 32 and hair 33 knotted to said hair-secured frame 32 is currently in wide use, as, in addition to its lightness and excellent air permeability, the appropriate desired hair-increasing treatment is possible, and arbitrary variation of hair style can be expressed, fully utilizing the user's own hair.
The rib cage-shaped hair-increasing device 30 comprises a hair-secured frame 32 having a connecting rib 32a at the center and a plurality of ribs 32b extending at both sides from said connecting rib 32a, and is formed by curving along the user's head shape (See Patent reference 1).
Hair 33 is knotted densely to respective ribs 32a and 32b of said hair-secured frame 32, though only its portion is shown in FIG. 13, and most of hair 33 is omitted.
Hair 33 is knotted to respective ribs 32a and 32b of said hair-secured frame 32 by the above-mentioned known knotting.
FIG. 14 is an enlarged diagonal view schematically illustrating hair flow of the hair 33 knotted by, for example, half-knot planting.
A strand of hair or a few strands of hair 33 are bound and bent at a center, and said bent portion is secured with knots 33c formed in 32a and the ribs 32b. 
Here, the term “planting” or “hair planting” is used to convey the concept which would widely include the cases to knot hair to linear members or to attach hair on a film-like wig base by sewing or bonding.
However, in cases where hair is attached on said net base or to a hair-secured frame, since filaments or ribs (hereinafter, these are termed as linear members as a whole) are all made of thin and long linear members, hair is wound and knotted to said linear members by using known hair planting arts such as single, half-knot, and split-knot plantings.
Therefore, unlike hair planting to artificial skin, the flow of the hair attached to filaments or ribs has to be restricted in a certain direction.
That is, in either case of a net member or a hair-secured frame, since it is formed by assembling linear members in matrix or diagonal direction, in case, for example, to knot hair to the linear members arranged in the forward and backward direction of a head, hair flow is necessarily in the direction in which one end portion and the other of the knotted hair are both orthogonally crossing to the linear members, that is, divided left and right, and hence the backward hair flow is difficult in case, for example, back style is desired.
Explanation is made here, referring to FIGS. 15-17, of the case to apply the known single, half-knot and split-knot planting to said linear member 32b arranged in back and forth direction of the hair-secured frame as shown in FIG. 14 to knot hair 33.
In FIG. 15, the upper end of the linear member 32b is assumed to be arranged in the forehead direction, and the lower end in the backhead direction.
The single planting is the method to form a loop 34 by twisting the bent hair 33 (See FIG. 15(A)), winding said loop 34 from the lower to the upper side of the linear member 32b with a hair-tying needle, and to knot after pulling out both one end portion 33a and the other end portion 33b of hair from the loop 34 (See FIGS. 15 (B) and (C)).
Therefore, both one end portion 33a and the other end portion 33b of the hair knotted by single planting are horizontally supported in the right angle direction to the linear member 32b arranged in the back and forth direction of the head, forming the right side hair flow in the figure.
The half-knot planting is, as shown in FIG. 16, the method to form a loop 34 by twisting the bent hair 33 (See FIG. 16(A)), winding said loop 34 like the above-mentioned case from the lower to the upper side of the linear member 32b with a hair-tying needle (See FIG. 16(B)), and next to knot only the other end portion 33b of hair to the linear member after pulling out from the loop 34 (See FIG. 16(C)). By this method, the leftward and rightward direction hair flow is formed in which one end portion 33a of hair orthogonally crosses to the left side of the linear member 32b, and the other end portion 33b to the right side in the figure, and both one end portion and the other end portion of hair do not stand up in the planted state, but are knotted as the lying state.
The split-knot planting shown in FIG. 17 is the method to form a loop 34, as shown in (A), by twisting clock-wise the bent hair 33 (See FIG. 17(B)), to form a second loop 35 like the above-mentioned case with the other end portion 33b by passing the other end portion 33b of hair through the loop 34 (See FIG. 17(C)), and next to knot one end portion 33a to the linear member after pulling out from the second loop 35 (See FIG. 16(D)). By this method, one end portion 33a of hair stands diagonally upward with regard to the linear member 32b in the figure, but the other end portion 33b lies to the left of the linear member to form a crossing hair flow. Here, since a loop 34 is formed by clock-wise twisting in the illustrated example, the hair flow like one end portion 33a and the other end portion 33b of hair of FIG. 17(D) is formed, but if a loop 34 is formed by anticlock-wise twisting and knotted sequentially, the other end portion 33b of hair stands diagonally upward with regard to the linear member 32b, but one end portion 33a lies likewise in the orthogonal direction to the linear member to form crossing hair flow.
[Patent Reference 1] JP Laid-open publication 2002-115115 A